Hi David, > Dear All, > > I'm a bit new to stereo modes (so take pity on me), but are any of the OSG > supported stereo modes (QUAD_BUFFER, *_INTERLACE, *_SPLIT, *_EYE, > ANAGLYPHIC) the same thing as "field sequential"? I guess I know that the > interlace/split/anaglyphic ones are out, but I was not sure what > quad_buffer actually supported...
Field-sequential stereo means that the frames are sent in a time-multiplexed manner - i.e. first left image, then right image, then left image, then right image, etc. This is typically used with shutter glasses, with an extra wire to synchronize them. OSG supports this mode using the QUAD_BUFFER mode. However, to have this work you need a graphic card and driver that support it - that is typically something from the nVidia Quadro range or ATI FireGL. The consumer hardware (GeForce, Radeon) has it disabled and typically lack the extra mini DIN synchronization connector (three pin, round connector, similar to the old PS/2 mouse connector). nVidia has something called "consumer stereo" driver for GeForce that will generate frame-sequential stereo imagery by intercepting the DirectX/OpenGL pipeline, moving the camera and rendering each frame twice for you, however I cannot recommend it. It is incredibly difficult to get to work (the Windows- only drivers work only with specific versions of ForceWare in Windows, usually very old ones that do not support current hardware), it is unstable and you have little control over the stereo settings. Also, it doesn't actually give you QUAD_BUFFER support, so you need to render normally and pray that the driver does its magic and you get a somewhat correct stereo output. > > Has anybody tried to get these things ( > http://www.personaldisplay.com/content/fmds/fmd_sub02_01.asp, and related > models) working with OSG? > That should be pretty easy to get working with a Quadro, set to synchronize via the DDC pin on the VGA connector. Set OSG to QUAD_BUFFER mode and off you go. Unfortunately, what they do not tell you in their sales pitch is that you need at least one of the high-end Quadros (about 800 USD+ investment for the cheapest one) to have this to work - the lower end stuff doesn't support stereo ... The FX605 seems to be a better option - it takes two VGA inputs where you feed both images in parallel (HORIZONTAL_SPLIT or VERTICAL_SPLIT OSG mode). That you can feed with any graphic card with two VGA outputs, even an old GeForce will do. This way of feeding the HMD is common on the higher-end hardware as well, in case you would like to upgrade later. Regards, Jan
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